A reconceptualization of the problem of collective decisions

Exchange theory has recently assumed an important place in sociological theory. However, exchange theory takes as its problem how resources are distributed among actors, and does not consider the allocation of resources towards producing different outcomes of events. This paper defines the problem of collective decisions as how a collectivity uses its resources to produce outcomes as a result of exchange and allocation. A model is presented that includes actors, events, and resources and their relationships in terms of interests, requirements, and control. The concepts are given a mathematical interpretation in an extension of Coleman's exchange model. This approach allows examination of the relationships between the individual and collective levels of analysis; it leads to the expectation of certain consistencies at the aggregate level; and it allows consideration of the consequences of changes in the ways resources may be used to affect event outcomes.     

Investigation of corannulene for molecular hydrogen storage via computational chemistry and experimentation

Molecular simulations for hydrogen physisorption with corannulene molecules arranged according to their crystal structure result in good agreement with the weight-percent hydrogen stored as determined experimentally employing a 3-g sample of highly crystalline corannulene at ambient temperatures and 72 bar of pressure. Calculated enthalpies of adsorption for corannulene/hydrogen molecular systems obtained from ab initio calculations which take into account electron correlation via second-order M?ller-Plesset perturbation theory are in good agreement with literature experimental enthalpies of adsorption for activated carbons interacting with molecular hydrogen. Ab initio results also show that corannulene molecules arranged in a sandwich structure are important for approximately doubling the binding energy of corannulene interacting with molecular hydrogen through a cooperative interaction. To test the effects of finite temperatures and pressures, stack arrays were used as input for molecular dynamics simulations and indicate that physisorption mechanisms including van der Waals forces and dipole-induced dipole interactions may yield enhanced adsorption capacity in relation to other carbon-based materials. These results will be instrumental in identifying interlayer separations of an array of corannulene or related molecules that may provide a high weight percent of physisorbed hydrogen.     

Phase-referenced interferometer with subwavelength and subhertz sensitivity applied to the study of cell membrane dynamics

We report a highly sensitive means of measuring cellular dynamics with a novel interferometer that can measure motional phase changes. The system is based on a modified Michelson interferometer with a composite laser beam of 1550-nm low-coherence light and 775-nm CW light. The sample is prepared on a coverslip that is highly reflective at 775 nm. By referencing the heterodyne phase of the 1550-nm light reflected from the sample to that of the 775-nm light reflected from the coverslip, small motions in the sample are detected, and motional artifacts from vibrations in the interferometer are completely eliminated. We demonstrate that the system is sensitive to motions as small as 3.6 nm and velocities as small as 1 nm/s. Using the instrument, we study transient volume changes of a few (approximately three) cells in a monolayer immersed in weakly hypotonic and hypertonic solutions.     

Optical bistability induced by mirror absorption: measurement of absorption coefficients at the sub-ppm level

We have observed optical bistability caused by absorption-induced thermal expansion of mirrors forming a Fabry-Perot interferometer. From the resulting anomalous transmission line shapes, absorption coefficients of the mirror coatings as low as 0.2parts in 10(6) (ppm) have been successfully measured.     

Polyimides derived from 1,2-bis(4-aminophenoxy)propane

The diamine 1,2-bis(4-aminophenoxy)propane, containing the flexible 1,4-dioxa-2-methylbutyl-ene unit, was synthesized. Polyimidization was carried out with 5,5′-[2,2,2-trifluoro-(trifluoromethyl)ethylidine]bis-1,3-isobenzofurandione in m-cresol employing toluene as azeotroping agent to yield a polyimide that was soluble in a variety of solvents and had an inherent viscosity of 0.84 dL/g in N,N-dimethylformamide. Poly(amic acid) formation with pyromellitic dianhydride, 4,4′-carbonyldiphthalic anhydride, and 5,5′-[ethanediylbis(oxy)]-bis-1,3-isobenzofurandione was carried out in N,N-dimethylformamide with imidization completed by heating at 160°C for 24 h under vacuum. All of the polyimides exhibited a 5% weight loss in air and in helium by 420°C.     

Voting in one's head as a source of nearly transitive individual preferences over multi-dimensional issues

We consider choices over alternatives in a multidimensional issue space. Individuals may make choices in a way that is analogous to majority rule processes in a group, i.e. individuals may act as if they had several different perspectives, each represented by a particular ideal point. Individuals then may express preferences that are derived from an internal majority rule process among individual's ideal points. This process of internal majority voting can give rise to intransitivities in much the same way as for majority rule in group decision making. However, the nature of these alternatives is constrained because of the geometry of the multidimensional issue space, so as to give rise to what we may characterize as a fuzzily transitive ordering. In that ordering, one alternative may be preferred by the individual to another if the former is closer to a point in the space that we call the center of the voter shell than is the other alternative.     

Secondary ion mass spectra of gold super clusters up to 140000 dalton

The bombardment of a two-shell gold complex (Au₅₅(PPh₃)₁₂Cl₆) with 10 keV Xe⁺-ions results in the formation of secondary ion masses up to 140000 u. These are by far the largest secondary ions observed under primary particle bombardment. The detection and identification of these ions with a Time-Of-Flight Secondary Ion Mass Spectrometer (TOF-SIMS) gives important information about the behavior of naked full-shell clusters. Au₁₃ particles, generated from the Au₅₅ cluster, serve as building blocks for a series of super-clusters up to (Au₁₃)₅₅. The results for keV-ion bombardment are compared to those for MeV-ion bombardment.     

Examination of some reversed-phase high-performance liquid chromatography systems for the determination of lipophilicity

Three reversed-phase systems [based on the divinylbenzene-styrene copolymer (PRP-1), the C₁₈-derivatized divinylbenzene-styrene copolymer (ACT-1), and the Nucleosil C₈ columns] were studied for their suitability in lipophilicity determination. Acetonitrile-water was selected as the mobile phase. Correlation between log k′ and log P_cyc for both the PRP-1 and Nucleosil C₈ systems was superior to the correlation between log k′ and either log P_oct or log P_cyc (oct = octanol; CYC = cyclohexane) on the ACT-1 column. On the PRP-1 and Nucleosil columns, correlation between log k′ and log P_oct was much improved when test compounds were grouped into classifications of non-H bonding, single amphiprotics (alcohols, phenols, amides) or double amphiproties. Although the PRP-1 system gave broad peaks with lipophilic substrates, there was good correlation between log k′ values on the Nucleosil silica-based reversed-phase system and the polymer PRP-1 system, indicating that either is suitable for the determination of lipophilicity.